Question

*The rate of change of the volume of a snowball that is melting is proportional to the surface area of the*

* snowball. Suppose the snowball is perfectly spherical. Then the volume (in centimeters cubed) of a ball of radius r centimeters is *4/3 π*r*3*. The surface area is *4π*r*2*. Set up the di*ff*erential equation for how r is changing. Then, suppose that at time t *= 0 *minutes, the radius is 10 centimeters. After 5 minutes, the radius is 8 centimeters. At what time t will the snowball be completely melted.*